Fix various problems around projects board view (#30696)

# The problem
The previous implementation will start multiple POST requests from the
frontend when moving a column and another bug is moving the default
column will never be remembered in fact.

# What's changed

- [x] This PR will allow the default column to move to a non-first
position
- [x] And it also uses one request instead of multiple requests when
moving the columns
- [x] Use a star instead of a pin as the icon for setting the default
column action
- [x] Inserted new column will be append to the end
- [x] Fix #30701 the newly added issue will be append to the end of the
default column
- [x] Fix when deleting a column, all issues in it will be displayed
from UI but database records exist.
- [x] Add a limitation for columns in a project to 20. So the sorting
will not be overflow because it's int8.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/web.go

@@ -37,6 +37,7 @@ import (
 	"code.gitea.io/gitea/routers/web/repo"
 	"code.gitea.io/gitea/routers/web/repo/actions"
 	repo_setting "code.gitea.io/gitea/routers/web/repo/setting"
+	"code.gitea.io/gitea/routers/web/shared/project"
 	"code.gitea.io/gitea/routers/web/user"
 	user_setting "code.gitea.io/gitea/routers/web/user/setting"
 	"code.gitea.io/gitea/routers/web/user/setting/security"
@@ -999,6 +1000,7 @@ func registerRoutes(m *web.Route) {
 				m.Post("/new", web.Bind(forms.CreateProjectForm{}), org.NewProjectPost)
 				m.Group("/{id}", func() {
 					m.Post("", web.Bind(forms.EditProjectBoardForm{}), org.AddBoardToProjectPost)
+					m.Post("/move", project.MoveColumns)
 					m.Post("/delete", org.DeleteProject)
 
 					m.Get("/edit", org.RenderEditProject)
@@ -1354,6 +1356,7 @@ func registerRoutes(m *web.Route) {
 			m.Post("/new", web.Bind(forms.CreateProjectForm{}), repo.NewProjectPost)
 			m.Group("/{id}", func() {
 				m.Post("", web.Bind(forms.EditProjectBoardForm{}), repo.AddBoardToProjectPost)
+				m.Post("/move", project.MoveColumns)
 				m.Post("/delete", repo.DeleteProject)
 
 				m.Get("/edit", repo.RenderEditProject)